the fbi missed things or our laws do not allow the fbi to follow up in a sound solid way. >> reporter: while officials cyst through the details worshipers sought answers in their own way gathering at the holy cross on sunday to reflect on the terror that the city faced in the last week. the governor says there can be vigilance without fear. >> there are lessons that we will have to learn and have learned painfully through this last experience that will have to be applied to future marathons. there will be future marathons. and they will be bigger and better. >> reporter: according to a person, they are still looking at the cause of death of tamerlan tsarnaev. >> the three people killed in the explosions as well as a fallen mit police officer sun collier were rememberedberg a prayer service today. as you can see, flowers were left near the finish line. the mayor has asked americans to observe a moment of silence at 2:50 in the afternoon. that is the time that the first of the two bombs went off. >> as the focus of the boston bombings turns to the legal aspect, one california senator is